Fluid pressure sensing devices

ABSTRACT

Disclosed are a fluid pressure sensing device and system for selectively inflating flotation equipment, e.g., life saving vests, jackets, rafts, etc. wherein, when the pressure of the fluid exterior to a fluid pressure sensing member thereof substantially reaches a selected fluid pressure, e.g., two feet of water, a resilient member thereof, e.g., an &#39;&#39;&#39;&#39;0&#39;&#39;&#39;&#39; ring, is forced out of sealing engagement with a geometrically shaped slot selectively formed in the inner wall of the fluid sensing member and fluid, such as water, enters through geometrically shaped openings selectively formed in the bottom wall of the geometrically shaped slot and into a cavity formed in the fluid pressure sensing member; wherein the fluid dissolves a fluid soluble member positioned within said cavity, e.g., a water soluble disc, and thereby releases a gas control or releasing member thereof, e.g., a spring biased slidable shaft having a pointed end thereon; whereby the gas control member moves to its gas releasing position, e.g., the pointed end of the slidable shaft pierces a frangible seal on a CO2 bottle or cartridge and permits passage of the gas from the gas storing member to the flotation equipment for inflation thereof.

United States Patent [191 Middleton, Jr.

[ Apr. 9, 1974 FLUID PRESSURE SENSING DEVICES William J. Middleton, Jr.,607 E. Spring Valley Rd., Richardson, Tex. 75080 [22] Filed: Apr. 19,1972 [21] Appl' No.: 245,370

[76] Inventor:

[52] US. Cl 9/317, l37/516.l5, 137/525 [51] Int. Cl. B63c 9/16 [58]Field of Search 9/316-320,

Primary Examiner-George E. A. l-lalvosa Assistant Examiner-Paul .E.Sauberer Attorney, Agent, or Firm-Michael A. Sileo, Jr.

57 ABSTRACT Disclosed are a fluid pressure sensing device and system forselectively inflating flotation equipment, e.g., life saving vests,jackets, rafts, etc. wherein, when the pressure of the fluid exterior toa fluid pressure sensing member thereof substantially reaches a selectedfluid pressure, e.g., two feet of water, a resilient member thereof,e.g., an 0" ring, is forced out of sealing engagement with ageometrically shaped slot selectively formed in the inner wall of thefluid sensing member and fluid, such as water, enters throughgeometrically shaped openings selectively formed in the bottom wall ofthe geometrically shaped slot and into a cavity formed in the fluidpressure sensing member; wherein the fluid dissolves a fluid solublemember positioned within said cavity, e.g., a water soluble disc, andthereby releases a gas control or releasing member thereof, e.g., aspring biased slidable shaft having a pointed end thereon; whereby thegas control member moves to its gas releasing position, e.g., thepointed end of the slidable shaft pierces a frangible seal on a C0bottle or cartridge and permits passage of the gas from the gas storingmember to the flotation equipment for inflation thereof.

7 Claims, 12 Drawing Figures ZATENTEDAPR 9 \974 I Y 3802.012

sum 2 OF 2 FLUID PRESSURE SENSING DEVICES PRIOR ART AND BACKGROUNDINFORMATION There exists a present need for a technically simple,relatively inexpensive, yet highly reliable fluid pressure sensingdevice for automatically inflating life saving flotation equipments.Skilled artisans in this field of technology have recognized thatwearability of life saving equipment is an important characteristic, noless important than any other characteristic including reliability anddurability. This is a fundamental truth because the most reliable anddurable life saving equipment is ineffectual if the user is not wearingsuch equipment when an accident or emergency occurs. Such factors asweight, bulk and comfort are important characteristics in whether or notthe flotation equipment will be worn by the userjlt is an establishedfact that inflatable life saving equipment per se are more comfortable,weigh less and are less bulky prior-to inflation than presently CoastGuard approved conventional foam or kapok filled life saving equipment.However, such conventional equipments have the advantage that the userdoes not have to do anything but wear the equipment to obtain adequateflotation support during emergencies. Thus, it is a desireable featurethat life saving equipment preferably does not require conscious usereffort to render such equipment operable prior to emergency use. Aninflatable life saving jacket, for example, preferably should beautomatically inflated without conscious user participation once theuser is immersed in water or quickly thereafter, e.g., within severalseconds after water entry, such as twenty seconds or sooner. Wateractuated life saving equipment will automatically operate without userawareness within several seconds after water entry but areunsatisfactory because such equipments prematurely operate due toexcessive water vapor, moisture accumulation, and water exposure, i.e.,when subjected to standing water, splashing, rain, or the like.Accordingly, life saving equipment of the gas inflatable type must bewater tolerant during storage and when being worn prior to wateremergency, but must automatically operate without user awareness whenthe user is inadvertently immersed in water by virtue of an emergency.Of course, manual user override of the automatic feature for intentionalinflation of the life saving equipment when an emergency is imminent orprobable is another desireable feature.

The prior art is replete with water actuated devices for automaticallyinflating flotation equipment when the device is immersed in water.

One type of water actuated inflation device utilizes water soluble bandswhich circumscribe the release handle or lever for actuating the device(see U.S. Letters Patent No. 3,266,668, issued Aug. 16, 1966). Anothertype of water actuated inflation device utilizes restricting members ofvarious shapes and geometries to hold a spring in a compressed position,such restricting members having sufficient strength to hold thecompressed spring when dry but loses its strength when wet, whereby whenthe device is immersed in water the restricting member releases thespring and actuates the device (see U.S. Letters Patents No. 3,490,648,issued Jan. 20, I970 and No. 3,494,506, issued Feb. l0, I970). Anothertype of water actuated inflation device utilizes a water soluble memberof various shapes and geometries which has sufficient strength when dryto hold a spring in a compressed state but disintegrates or dissolveswhen wet so as to" release the spring and thereby actuate the device(see U.S. Letters Patent No. 3,526,339, issued Sept. 1, 1970). Anothertype of water actuated inflation device utilizes a battery operatedexplosive member, the battery of which when dry does not produceelectrical energy but does produce electrical energy when wet, whereuponwhen the device is immersed in water, the battery ignites the explosivemember which in turn propels a piston that punctures the seal of a gasstorage member to thereby actuate the device (see U.S. Letters PatentNo. 3,266,669, issued Aug. 16, 1966). Another type of water actuatedinflation device utilizes a source of electrical power and a pair ofspaced apart conductors which when wet trigger a thyristor switch toclose an electric circuit and thereby actuate the device (see U.S.Letters Patent No. 3,426,942, issued Feb. ll, 1969 Pressure sensitiveinflation devices of various constructions have heretofore been made,but in the most part have not been completely satisfactory by virtue ofthe fact that such prior known devices have been generally complex inconstruction, expensive to'manufacture and generally unreliable, withsome of them utilizing battery storage members requiring periodic checksand maintenance to ensure operability. For example, one type of pressuresensitive inflation device utilizes a flexible diaphragm and associatedpiston which moves proportional with the pressure external to the deviceuntil it releases an actuating member which in turn may ignite anexplosive charge or close a circuit, the happening of which releasespressurized fluid for inflation or the like (see U.S. Letters Patent No.3,349,786, issued Oct. 31, 1967). Another example of a pressuresensitive inflation device utilizes a resilient pressure sensitivediaphragm sealed across an opening which stretches upon immersion inwater to a predetermined depth so as to release a trigger member andthereby actuate the device (see U.S. Letters Patent No. 3,490,649,issued Jan. 20, 1970).

Although the aforementioned prior known techniques and apparatus forautomatically actuating inflation devices of various types have beensatisfactory in many respects, there still remain several unsatisfactoryfeatures and functions that have confronted the skilled artisan in theart to which they pertain, such as, device reliability, technicalcomplexity, high maintenance requirements, high manufacturing costs,durability and user wearability.

The several embodiments of this invention as hereinafter describedadvantageously overcome the aforementioned unsatisfactory features andfunctions in a simple, relatively inexpensive and highly reliablemanner, yet advantageously provide a device that is relatively lightweight, compact and comfortable.

BRIEF DESCRIPTION OF INVENTION This invention relates to a fluidpressure sensitive device for selectively controlling the passage of gasfrom a gas inlet to a gas outlet thereof, and more particularly relatesto a fluid pressure sensitive device for selectively inflating flotationequipment, such as, life saving vests, jackets and rafts.

In one embodiment of the invention the fluid pressure sensing deviceincludes: Gas Control Means for controlling the passage of gas from gasstorage means to flotation equipment which is selectively movable into agas releasing position; Restraint Means including Fluid Soluble Meansfor selectively inhibiting the Gas Control Means from moving into itsgas releasing position; and Fluid Pressure Sensing Means connected tothe Gas Control Means for sensing a selected fluid pressure externalthereof. One embodiment of the Fluid Pressure Means of this inventionincludes a main body portion including a cavity which is releasablyconnected to the Gas Control Means. A geometrically shaped slot isformed in the inner wall of the main body and geometrically shapedopenings selectively formed in the bottom wall of the geometricallyshaped slot for providing an unimpeded path for fluid flow from theexterior of the Fluid Pressure Sensing Means through the openings andslot to the cavity of the main body portion. Resilient Means arepositioned within the cavity of the main body portion in sealingengagement with the geometrically shaped slot for sealing thegeometrically shaped openings and inhibiting fluid from entering thecavity of the main body.

By this novel construction, when the pressure of the fluid exterior tothe Fluid Pressure Sensing Means reaches a selected fluid pressure, theResilient Means is forced out of sealing engagement with thegeometrically shaped slot, fluid enters the cavity and dissolves theFluid Soluble Means, which in turn releases the Restraint Means,whereupon the Gas Control Means moves to its gas releasing position andpermits passage of gas from the gas storage means to the flotationequipment for inflation thereof.

In another embodiment of the invention, the fluid pressure sensingdevice includes Housing Means having a geometrically shaped cavityformed therein and a gas outlet and inlet selectively located thereon;Gas Controlling Means for selectively controlling the passage of gasfrom the gas inlet to the gas outlet which is selectively moveable froma gas inhibiting position to a gas releasing position; Restraining Meansfor releasibly holding the Gas Control Means in its gas inhibitingposition which include a fluid soluble member; Biasing Means for movingthe Gas Control Means into its gas releasing position which isrestrained from operation by the Restraining Means; Pressure SensingMeans including a pressure sensing head having a central chamber andselectively positioned slots formed therein with associated openings anda resilient member positioned within the slots for sealing the openingsand inhibiting fluid from entering the chamber. By this latter novelconstruction, when the external fluid pressure reaches a selected value,the resilient member is forced out of its sealing position to allowfluid to enter the chamber, whereupon the soluble member dissolves, theRestraining Means releases the Biasing Means and the Gas Control Meansis biased into its Gas releasing position, thereby permitting passage ofgas from the gas inlet to the gas outlet.

lt is contemplated that the resilient member may be of various geometricshapes, such as, ring-like, a solid or hollow sphere, band-like, or afull or partial tube, so long as its shape and resilient characteristicsin structural combination with the shape of the slots formed in theinner wall of the pressure sensing head cooperate effectively to sealsuch slots and the associated openings and inhibit fluid from enteringthe chamber or cavity thereof until the external fluid pressure reachesa selected value.

OBJECTS OF THE INVENTION It is one object of this invention to provide apressure sensing device for selectively allowing gas to pass from a gasinlet to a gas outlet thereof.

Another object of this invention is to provide a fluid pressure sensingdevice for selectively inflating flotation equipment, such as lifesaving vests, jackets and rafts, when the device is immersed in water toa se lected depth.

Another object of this invention is to provide a pressure sensing deviceof the type described herein which is uniquely tolerant to water vapor,moisture accumulation, humidity, water exposure, or the like, and onlyoperates automatically when immersed in water and subjected tohydrostatic pressure which is capable of causing operation of thedevice, such as two feet of water.

Another object of this invention is to provide a pressure sensing deviceof the type described herein which prevents the passage of gas from gasstorage means to flotation means for inflation thereof until thepressure of the fluid exterior to the device reaches a selectedhydrostatic pressure.

Another object of this invention is to provide an automatically actuatedpressure sensing device of the type described herein that includes amanual override capability for selectively inflating flotation meansprior to an emergency condition without adversely affecting theautomatic pressure sensing capability of the device.

Another object of this invention is to provide a pressure sensing devicerequiring relatively fewer pressure sensing members, yet advantageouslysenses hydrostatic pressures of relatively small pressure differentials.

Another object of this invention is to provide a pressure sensing deviceof the type described herein which advantageously provides improvedwearability, yet adequately achieves satisfactory reliability anddurability.

Another object of this invention is to provide a pressure sensing deviceof the type described herein which is technically simple, relativelyinexpensive to make, highly reliable and durable, yet being relativelylightweight, compact and comfortable to advantageously achieve improveduser wearability.

These and other objects and features of this invention will be readilyapparent from the following description when taken in conjunction withthe appended claims and attached drawings.

BRlEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cross-sectionedand partially cutaway view of a fluid pressure sensing device forselectively inflating flotation equipment in accordance with oneembodiment of the present invention, with the lanyard and manual leverthereof in a manual override position shown in phantom.

FIG. 2 is a perspective view of the clevis and bore plug assembly,manual actuation lever, coaxial sleeve and drive pin and piercing pin ofHO. 1

FIGS. 3-5 are cross sectional views of alternate embodiments of theflexible member of the pressure sensing head in accordance with thisinvention.

FIG. 6 is a top plan view of the pressure sensing head of FIG. 1.

FIG. 7 is a cross sectional view of the pressure sensing head takenalong the view plane 7-7 of FIG. 6.

FIG. 8 is a cross sectional view of the pressure sensing head of FIG. 7taken along the view plane 88 with the flexible member removed forclarity and graphic simplicity.

FIG. 9 is a perspective view with partial cut-away portions of asubverter cap in accordance with this invention.

FIG. 10 is a perspective view with partial cross section of the pressuresensing head of FIG. 1 with the subverter cap of FIG. 9 secured in itssubverting position.

FIGS. 11 and 12 are cut away, partially sectioned views of the flexiblemember of FIG. 1 respectively in its sealing and non-sealing position.

DETAILED DESCRIPTION A detailed description of several embodiments ofthis invention follows with reference being made to the drawings whereinlike parts have been given like reference numerals for clarity andunderstanding of the elements and features of this invention.

Referring to FIGS. 1 and 2, there is generally shown a fluid pressuresensing device for selectively inflating flotation equipment (hereafterPS Device) in accordance with one embodiment of this invention which isreadily adaptable for use with a standard inflatable life vest, jacketor raft. The PS device includes a main body portion 10 having a mountinghole 12 of standard shape and dimension for releasably securing the PSdevice to a standard inflatable life vest, jacket or raft. At one end ofthe main body 10 is an internally threaded opening 14 for releasablysecuring a gas storage member 15, such as a standard C0 cartridge. Toensure gas sealing integrity between the gas storage member 15 and theinternal cavity 16, a gasket 18 is provided which abuts the end wall ofopening 14. The other end of the main body 10 has an externally threadedshank 21 upon which is threadably secured an internally threaded bonnet22.

A clevis and bore plug assembly, generally indicated at 24, isreleasably secured within the cavity 16 by the bonnet 22. This assemblyincludes a clevis 26 having a transverse slot formed at one end, a crosspin 28 for holding a lever 30 in position thereon, a shoulder portion 32for positioning and clamping the clevis 26 with respect to and upon themain body 10, and a flexible O ring seal 34 for preventing egress andingress of unwanted fluids out of and into the cavity 16. A sleeve 36having a diameter less than the diameter of the clevis 26 and coaxialtherewith is secured to or integral with the clevis 26. Coaxiallypositioned within the sleeve 36 is a drive pin 38 which is mountedtherein for slidable coaxial movement with respect to both the clevis 26and sleeve 36. The drive pin 38 has a head 40 at one end, and a flexibleO ring 44 positioned therebetween to prevent egress and ingress ofunwanted fluids out of and into the cavity 16. A piercing pin 46 havingone end laterally restricted and coaxially positioned within the centralbore 42 of the drive pin 38 and a pointed end coaxially positioned inclose proximity to the opening of the main body 10. Near the pointed endof the piercing pin 46 is a piston 50, which is secured thereto bywelding or brazing, or preferably it is threadably secured formaintenance purposes, with a flexible O ring 52 mounted thereon to keepthe gas emitted by the gas storage member 15 in the portion of cavity 16which is between the piston and the small opening 20. Between the piston50 and the end wall 19 is positioned a return spring 53 to ensure thatthe piston is returned a sufficient distance from the end wall 19 afteractuation of the PS device so as to allow gas to egress therefromthrough the outlet 55. Thus, gas emitted from the gas cartridge 15passes through the opening 20, enters the cavity 16 and exhausts out theoutlet 55 to the flotation device (not shown) connected thereto.

Positioned concentrically about the sleeve 36, drive pin 38 and piercingpin 46, within the cavity 16, is a hammer or striker 54 having a largerrear portion 56 and a smaller front portion 58, joined by a taperedportion or restraining shoulder 60. Secured at the front end of thehammer 54 is an enlarged head portion 62. The hammer 54 is preferablyhollow so that it can move axially within the cavity 16 independent withrespect to the drive and piercing pins 38,46. A helical spring 64 isconcentrically mounted within the hollow of the hammer 54 with one ofits ends abutting the inner shoulder 66 and its other end abutting theclevis 26. By this construction, when the hammer 54 is in the positionas shown in FIG. 1, the spring 64 is compressed thereby biasing thehammer 54 toward the right end of the main body 10.

Releasably secured at the opposite end of the main body 10 is a handle68, which has an opening 70 formed in its enlarged outer end 72 and alongitudinal slot formed in its smaller inner end 74. An externallythreaded shank 76 is secured to or integrally formed with the enlargedouter end 72 for storing a subverter cap 78 when not in use. Subvertercap 78 has a resilient ring-like member 79 secured to the peripheraledge of its open end and will be further described hereinbelow withregard to the mode of operation of the PS device. The smaller inner end74 has a central bore formed therein which is shaped to conform to theouter end of the main body 10. Handle 68 is fitted upon the outer end ofthe main body 10 so that when it is pulled away from the main body 10,it easily slides off, yet fits snugly in place so as to remain thereonduring normal use of the PS device. To ensure proper relativepositioning of the handle 68 with respect to the main body 10, an innerperipheral shoulder 80 is formed at a selected distance within thecentral bore to prevent the handle 68 from sliding too far down the mainbody 10. The central bore in the handle 68 preferably terminates at theenlarged portion of the handle. The lever 30 is positioned within theslot 74 of the handle 68, while the lanyard 82 is connected at one endto the lever 30 while its other end extends through the opening 70 ofthe handle 68 and secured therein by the knot 84.

The clevis 26, lever 30, drive pin 38, piercing pin 46, handle 68 andlanyard 82 combine to provide manual override of the automatic pressuresensing capability of the PS device, as will be described hereinbelow inmore detail.

Extending from the main body 10 is an externally threaded boss 86 havinga central bore 88 formed therein. Positioned within the central bore 88is a restraint pin 90 having a substantially flat upper end and aconical or tapered lower end 92 with a resilient O ring 94 positionedtherebetween. The tapered end 92 of the restraint pin 88 extends intothe cavity 16 and abuts the restraining shoulder 60 of the hammer 54 andholds the hammer 54 in the position shown in FIG. 1, to wit, the cockedposition of the PS device in readiness for actuation thereof or for thegas releasing mode of the PS device.

A pressure sensing head 96 is threadably secured to the threaded boss 86and tightly abutting the resilient washer 97, and includes a cup shapedbody 98, a central bore 100, and internal annular groove or slot,selectively positioned openings 102 which extend to the slot 103, anexternally threaded shank 104 and a transparent window 106. Positionedwithin the central bore 100 is a resilient member 108 which ispreferably an O ring that abuts and seals the annular slot 103.Circumscribing the lower end of the bore 100 is a fluid soluble member110, preferably disc shaped, that extends beyond the peripheral edgethereof and abuts the shoulder portion 1 12 of the body 98. The solublemember 110 is of the type that when dry has sufficient strength to holdthe restraint pin 90 in its hammer restraining position (as shown inFIG. 1) in opposition to the force exerted by the compressed spring 64against the hammer 54. However, when the soluble member 110 gets wet itloses its strength by dissolving or disintegrating and thereby releasesthe hammer 54.

The top of the restraint pin 90 is preferably painted a brightcolor,'such as red, so that when the soluble member has dissolved ordisintegrated, the user of the PS device is readily aware of theexpended condition by visual observance of the colored top of therestraint pin 90 as viewed through the transparent window 106.

The resilient member 108 of the pressure sensing head 96 is chosen tohave expansion and resilience characteristics which will satisfactorilyseal the annular groove 103 when the PS device is subjected to anexternal fluid pressure above a selected value, and will readilycompress and unseat itself at one or more areas along its periphery whenthe PS device is subjected to an external fluid pressure at or above theselected value. By this arrangement, the central bore 100 of thepressure sensing head 96 is maintained free of fluid until the selectedexternal pressure occurs, such as when the PS device is submerged to aselected depth of water. Thus, fluids and other contaminants areprevented from entering the central bore 100 so as to substantiallyenhance device reliability and uniquely achieve pressure sensingcapability primarily independent of chemical or electrical requirements.

Automatic operation of the PS device is as follows:

1. The elements and members are relatively positioned in mechanical andchemical cooperation as shown in FIG. 1 in readiness for a cycle ofoperation when the PS device is subjected to a selected external fluidpressure, such as submersion to two feet of water.

2. When the external pressure reaches the selected value, the fluid inthe slots 102 unseats the resilient member 108 from the annular groove103 and fluid enters the central bore 100 of the pressure sensing head96.

3. The fluid soluble member 110 is saturated with fluid and dissolves ordisintegrates, thereby releasing the restraint pin 90 so that it movesout of engagement with the hammer 54 but remains within the central bore88.

4. The compressed spring 64 drives the hammer 54 toward the piercing pinpiston 50, striking the piston 50 and driving it and the piercing pin 46with a force sufficient to penetrate the seal on the gas cartridge 15.The piercing pin preferably moves within the drive pin in a coaxialmanner therewith and is not secured thereto. The drive pin being used todrive the piercing pin only during manual operation of the PS device. Adetailed description of the manual operation of the PS device is setforth hereinbelow in detail.

5. The return spring 53, which is compressed when the piston 50 moves tothe right, biases the piston 50 and hammer 54 to the left a sufficientdistance to clear both the opening 20 and outlet 55.

6. Gas from the gas cartridge 15 passes through the opening 20, into thecavity 16, and out the gas outlet 55 to a flotation device (not shown)which is both mechanically and fluidly secured to the PS device via themounting hole 12 and gas outlet 55, respectively.

7. To reset the PS device, the handle 72 is pulled off the housing 10,the bonnet and pressure sensing head 96 are removed from the housing 10,and the expended gas cartridge 15 removed. All elements are thenthoroughly dried. A dry soluble member 110 is positioned over therestraint pin and the pressure sensing head 96 is threaded down on thethreaded boss 86, ensuring that the hammer 54 is positioned so that itsconical member 60engages the tapered end 92 of the restraint pin 90. Itis also important at this point to ensure that the resilient member 108is properly seated in sealing engagement with the annular groove 103.The bonnet 22 is then threaded down on the threaded end 21 of thehousing 10, thereby compressing the spring 64. Finally, the handle 72 isslid onto the housing 10 with the lever 30 and lanyard 82 in position asshown in FIG. 1.

Manual operation of the PS device is effected by pulling the handle 72away from the housing 10, which causes the lever 30 to pivot about thecross pin 40 due to the lanyard 82 which is connected therebetween. Theend of the lever 30 cams against the head 40 of the drive pin 38 whichmoves to the right and forces the piercing pin 46 to penetrate the sealon the gas cartridge 15, thus actuating the PS device. The return spring53 ensures that the piston 50 is adequately returned to a position toclear the opening 20 and outlet 55. Note, however, that when the PSdevice is manually operated, the hammer 54 does not move from theposition shown in FIG. 1 by virtue of the fact that the novel concentricsleeve configuration hereinabove described. Thus, by replacing the spentgas cartridge 15 after manual operation, the PS device is in readinessfor both subsequent manual and automatic operation without removal ofthe pressure sensing head 96 and without damage to the soluble member 110, provided of course the subverter cap 78 has been used, i.e., removedfrom the handle 72 and positioned upon the sensing head 96, as shown inFIG. 10.

The subverter cap 78 is provided for the purpose of preventing automaticactuation of the PS device for any reason, such as, by skin divers whomay desire to have automatic actuation after a dive when near thesurface, or by military personnel who may wish to subvert automaticoperation during certain water phases of a mission. In any event, if itis desireable to subvert automatic operation, the subverter cap 78 isthreadably 9 removed from the end of the handle 72 and threadablysecured to the pressure sensing head 96 until the resilient ring-likemember 79 is firmly compressed against the upper ledge of the cup member98, thereby preventing external fluid from exerting pressure against theresilient member 108 via the openings 102.

FIGS. 3-5 respectively show alternate embodiments of a resilient memberwhich may be substituted for the resilient member 108. FIG. 3 shows aresilient sphere 114 which may be solid or hollow, that abuts the inneredges of the annular groove 103 so as to be in sealing engagementtherewith. FIG. 4 shows a resilient band 115 that overlies and expandsagainst the annular groove 103 and abuts a portion of the inner surfaceof the cup member 104 so as to be in sealing engagement therewith. FIG.5 shows a resilient tube like member 116 which may be a half section asshown or a complete tube (not shown) that abuts the inner edges of theannular groove 103 so as to be in sealing engagement therewith. i

FIGS. 6 and 7 are respectively top plan and cross sectional views of thepressure sensing head 96 which are enlarged and graphically includedherein to assist in better understanding the structuralinterrelationships between the several parts thereof. In thisembodiment, the pressure sensing head is not threaded for uses in whichthe subverter capability is not desired.

FIGS. 9 and 10 respectively show the subverter cap 78 and a view of itsecured on the pressure sensing head 96, each with partial cut away forgraphic simplicity. Note that the resilient member 108 is visiblethrough the opening 102.

FIG. 8 is a cross sectional view of the pressure sensing head takenalong the view plane 88 with the resilient member 108 removed. Note thatthe annular groove 103 formed in the main body 104 intersects theopenings 102 to provide fluid path from the outside of the pressuresensing head 96 to the cavity thereof.

'FIGS. 11 and 12 are enlarged partial cross sectional views of theresilient member 108 respectively in its fluid sealing and non sealingpositions. Note that the resilient member 108 when in its fluid sealingposition firmly abuts the upper edges of the annular slot or groove 103,and is moved out of sealing engagement when in its non fluid sealingposition.

It will therefore be apparent from the foregoing description of severalembodiments of the present invention in light of the attached drawingsthat the fluid pressure device is uniquely tolerant to water vapor,moisture accumulation, humidity, water exposure, or the like, and onlyoperates automatically when immersed in water and subjected to ahydrostatic pressure capable of causing operation of the device, suchas, the hydrostatic pressure at two feet of water. Furthermore, suchnovel pressure sensing device requires relatively fewer pressure sensingmembers, yet advantageously senses hydrostatic pressures of relativelysmall pressure differentials, such device being technically simple,relatively inexpensive to make, highly reliable and durable, relativelylightweight, compact and comfortable.

The terms and expressions which have been employed herein are used asterms of description and not limitation, and it is not intended, in theuse of such terms and expressions, to exclude any equivalence of thefeatures shown and described, or portions thereof, but it is recognizedthat various modifications are possible within the scope of the presentinvention.

Without further elaboration, the foregoing is considered to explain thecharacter of the present invention so others may by applying currentknowledge, readily adapt the same for use under varying conditions ofservice, while still retaining certain features which may properly besaid to constitute the essential items of novelty involved, which itemsare intended to be defined and secured by the appended claims.

What is claimed is:

l. A fluid pressure sensing device for selectively inflating flotationequipment when the fluid pressure external thereto substantially reachesa selected pressure, comprising in combination:

a. gas releasing means for selectively controlling the passage of gasfrom gas storage means to flotation equipment and being movable from afirst position to a gas releasing position;

b. fluid pressure sensing means for selectively actuating said gasreleasing means'when said selected pressure occurs, said fluid pressuremeans including 1. a main body portion having a cavity formed therein,2. an annular groove formed in the inner wall of said main body portion,

3. at least one geometrically shaped stoped opening formed in said mainbody portion and extending intosaid annular groove for providing anunimpeded path for fluid flow from the exterior of said fluid pressuresensing means to said cavity,

4. fluid responsive means structurally capable of holding said gasreleasing means in its first position,

5. substantially non-metallic resilient means positioned within saidcavity in sealing engagement with said annular groove for sealing saidgeometrically shaped opening and for selectively inhibiting fluid fromentering said cavity; wherein c. said resilient means is mechanicallyforced out of sealing engagement with said annular groove when saidselected pressure occurs and fluid thereby enters said cavity throughsaid geometrically shaped opening, whereby,

d. said fluid responsive means selectively permits said gas releasingmeans to move to its gas releasing position which allows gas to flowfrom said storage means to said flotation equipment for selectedinflation thereof.

2. The fluid pressure sensing device of claim 1 and further includingmanual means for manually actuating said gas releasing member.

3. The fluid pressure sensing device of claim 1 wherein said resilientmeans is a solid or a hollow spherically shaped member.

4. The fluid pressure sensing device of claim 1 wherein said resilientmeans is a band like member.

5. The fluid pressure sensing device of claim 1 wherein said resilientmeans is a tube like member.

6. A fluid pressure sensing device for selectively inflating flotationequipment, comprising in combination:

a. gas storage means including a gas releasing member;

b. fluid pressure sensing means connected to said gas storage means foractuating said gas releasing member including l. a main body portionhaving a cavity formed therein,

2. an annular groove formed in the inner wall of said main body portion,

3. at least one geometrically shaped opening formed in said main bodyportion and extending into said annular groove for providing anunimpeded path for fluid flow from the exterior of said fluid pressuresensing means to said cavity,

4. resilient means positioned within said cavity in 1Q sealingengagement with said annular groove for sealing said geometricallyshaped opening and inhibiting fluid from entering said cavity;

5. transparent means for providing visual access to the interiorthereof, and 5 6. color means selectively located within said cavity;wherein c. when the pressure of the fluid exterior to said fluidpressure sensing means substantially reaches a selected pressure, saidresilient means is forced out of sealing engagement with said annulargroove and fluid enters said cavity through said geometrically shapedopening, actuating said fluid pressure sensing means, whereby said gasreleasing member is actuated, said flotation equipment is inflated,

and said color means is visually accessible through said transparentmeans. 7. A fluid pressure sensing device for automatically inflatingflotation equipment when the fluid pressure external theretosubstantially reaches a selected pressure, comprising in combination:

a. gas storage means for inflation b. gas control means for selectivelycontrolling the passage of gas from gas storage means to flotationequipment, said gas control means being moveable from a first positionto a gas releasing position;

c. fluid responsive means for holding said gas control means in itsfirst position, said fluid responsive means being structurally capableof holding said gas control means in its first position when dry butlosing said structural capability when wet;

d. fluid pressure sensing means connected to said gas control means forautomatically sensing said selected pressure and for automaticallyactuating said gas control means including 1. a main body portionreleasably connected to said gas control means and having a cavityformed therein;

2. an annular slot formed in the inner wall of said main body portion,

3. at least one geometrically shaped opening formed in said main bodyportion and extending into said annular slot for providing an unimpededpath for fluid flow from the exterior of said fluid pressure sensingmeans to said cavity of said main body portion, and

4. substantially non-metallic resilient means positioned within saidcavity of said main body portion in sealing engagement with said annularslot for sealing said opening and inhibiting fluid from entering saidcavity of said main body portion; wherein e. said resilient means ismechanically forced out of sealing engagement with said annular slotwhen said selected pressure occurs, and fluid thereby enters said cavitythrough said geometrically shaped opening, thereby diminishing thestructural capability of said fluid responsive means and releasing saidgas control means, whereby said gas control means moves to its gasreleasing position and permits passage of gas from said gas storagemeans to said flotation equipment for automatic inflation thereof.

1. A fluid pressure sensing device for selectively inflating flotationequipment when the fluid pressure external thereto substantially reachesa selected pressure, comprising in combination: a. gas releasing meansfor selectively controlling the passage of gas from gas storage means toflotation equipment and being movable from a first position to a gasreleasing position; b. fluid pressure sensing means for selectivelyactuating said gas releasing means when said selected pressure occurs,said fluid pressure means including
 1. a main body portion having acavity formed therein,
 2. an annular groove formed in the inner wall ofsaid main body portion,
 3. at least one geometrically shaped stopedopening formed in said main body portion and extending into said annulargroove for providing an unimpeded path for fluid flow from the exteriorof said fluid pressure sensing means to said cavity,
 4. fluid responsivemeans structurally capable of holding said gas releasing means in itsfirst position,
 5. substantially non-metallic resilient means positionedwithin said cavity in sealing engagement with said annular groove forsealing said geometrically shaped opening and for selectively inhibitingfluid from entering said cavity; wherein c. said resilient means ismechanically forced out of sealing engagement with said annular groovewhen said selected pressure occurs and fluid thereby enters said cavitythrough said geometrically shaped opening, whereby, d. said fluidresponsive means selectively permits said gas releasing means to move toits gas releasing position which allows gas to flow from said storagemeans to said flotation equipment for selected inflation thereof.
 2. anannular slot formed in the inner wall of said main body portion,
 2. anannular groove formed in the inner wall of said main body portion,
 2. anannular groove formed in the inner wall of said main body portion, 2.The fluid pressure sensing device of claim 1 and further includingmanual means for manually actuating said gas releasing member.
 3. Thefluid pressure sensing device of claim 1 wherein said resilient means isa solid or a hollow spherically shaped member.
 3. at least onegeometrically shaped stoped opening formed in said main body portion andextending into said annular groove for providing an unimpeded path forfluid flow from the exterior of said fluid pressure sensing means tosaid cavity,
 3. at least one geometrically shaped opening formed in saidmain body portion and extending into said annular groove for providingan unimpeded path for fluid flow from the exterior of said fluidpressure sensing means to said cavity,
 3. at least one geometricallyshaped opening formed in said main body portion and extending into saidannular slot for providing an unimpeded path for fluid flow from theexterior of said fluid pressure sensing means to said cavity of saidmain body portion, and
 4. resilient means positioned within said cavityin sealing engagement with said annular groove for sealing saidgeometrically shaped opening and inhibiting fluid from entering saidcavity;
 4. substantially non-metallic resilient means positioned withinsaid cavity of said main body portion in sealing engagement with saidannular slot for sealing said opening and inhibiting fluid from enteringsaid cavity of said main body portion; wherein e. said resilient meansis mechanically forced out of sealing engagement with said annular slotwhen said selected pressure occurs, and fluid thereby enters said cavitythrough said geometrically shaped opening, thereby diminishing thestructural capability of said fluid responsive means and releasing saidgas control means, whereby f. said gas control means moves to its gasreleasing position and permits passage of gas from said gas storagemeans to said flotation equipment for automatic inflation thereof. 4.fluid responsive means structurally capable of holding said gasreleasing means in its first position,
 4. The fluid pressure sensingdevice of claim 1 wherein said resilient means is a band like member. 5.The fluid pressure sensing device of claim 1 wherein said resilientmeans is a tube like member.
 5. substantially non-metallic resilientmeans positioned within said cavity in sealing engagement with saidannular groove for sealing said geometrically shaped opening and forselectively inhibiting fluid from entering said cavity; wherein c. saidresilient means is mechanically forced out of sealing engagement withsaid annular groove when said selected pressure occurs and fluid therebyenters said cavity through said geometrically shaped opening, whereby,d. said fluid responsive means selectively permits said gas releasingmeans to move to its gas releasing position which allows gas to flowfrom said storage means to said flotation equipment for selectedinflation thereof.
 5. transparent means for providing visual access tothe interior thereof, and
 6. A fluid pressure sensing device forselectively inflating flotation equipment, comprising in combination: a.gas storage means including a gas releasing member; b. fluid pressuresensing means connected to said gas storage means for actuating said gasreleasing member including
 6. color means selectively located withinsaid cavity; wherein c. when the pressure of the fluid exterior to saidfluid pressure sensing means substantially reaches a selected pressure,said resilient means is forced out of sealing engagement with saidannular groove and fluid enters said cavity through said geometricallyshaped opening, actuating said fluid pressure sensing means, wherebysaid gas releasing member is actuated, said flotation equipment isinflated, and said color means is visually accessible through saidtransparent means.
 7. A fluid pressure sensing device for automaticallyinflating flotation equipment when the fluid pressure external theretosubstantially reaches a selected pressure, comprising in combination: a.gas storage means for inflation b. gas control means for selectivelycontrolling the passage of gas from gas storage means to flotationequipment, said gas control means being moveable from a first positionto a gas releasing position; c. fluid responsive means for holding saidgas control means in its first position, said fluid responsive meansbeing structurally capable of holding said gas control means in itsfirst position when dry but losing said structural capability when wet;d. fluid pressure sensing means connected to said gas control means forautomatically sensing said selected pressure and for automaticallyactuating said gas control means including